Fluid-operated rpm regulator for internal combustion engines

ABSTRACT

Two fluid pulse signals of identical, r.p.m.-dependent frequency and of a predetermined relative time lag are applied to a fluid logic element to generate an r.p.m.-dependent output pressure which, in turn, is applied to a fluid amplifier element together with an arbitrarily variable fluid pressure. The amplified differential pressure is used directly to displace the fuel control rod of a fuel injection pump to increase or decrease the engine r.p.m.

I Unlted States Patent 1111 3,583,376

[72] Inventors lllroshi'l'onegawa [50] Field of Search 123/103, Kawagoe-shi; 97, 104, 108, 140.1, l40; l37/8l.5 Hiroshi lsobe; Tadayuki Kawasaki; Kenji Nakayama, lligashi-Matsuyana-shi, all of, References Cited Japan UNITED STATES PATENTS PP M 815,549 2,900,969 8/1959 Udale 123/140.1 1221 APP-14,1969 3,266,510 8 1966 Wadey 137/81.5 I451 3,292,648 12/1966 Colston 137/8l.5 1 1 Asslgnee lgflfiflbushlhhlsha 3,461,892 8/1969 Boothe etal 137/81.5X Priority p 15,1968 3,463,176 8/1969 Lazar 137/81.5X 33 Japan Primary ExaminerWendell E. Burns 3 43 24321 Attorney-Edwin E. Greigg ABSTRACT: Two fluid pulse signals of identical, r.p.m.-de- [54] FOR pendent frequency and of a predetermined relative time lag 7 Claims 6 Drawin s are applied to a fluid logic element to generate an r.p.m.-de-

8 lg pendent output pressure which, in turn, is applied to a fluid [52] U.S.Cl 123/103, amplifier element together with an arbitrarily variable fluid 123/97, 123/104, 123/108, 123/140, 137/8 1 .5 pressure. The amplified differential pressure is used directly to [51] lnt.Cl ..F0lc 21/12, displace the fuel control rod of a fuel injection pump to increase or decrease the engine r.p.m.

l7 El 3 22 21 ATENTED JUN 8 m: 3,583 376 FIG.1

INVENTOR FLUID-OPERATED RPM REGULATOR FOR INTERNAL COMBUSTION ENGINES BACKGROUND OF THE INVENTION This invention relates to a fluid- (liquid or gas) operated r.p.m. regulator for particular use in internal combustion engines that operate on injected fuel.

In known pneumatic r.p.m. regulators in which the engine r.p.m. is controlled by sensing the intake vacuum at the butterfly valve disposed in the suction tube, the change in the vacuum with respect to the change in the r.p.m. is small because of the large throttle opening with which the engine operates under heavy load conditions. As a result, the r.p.m.- adjustment or control is often insufficient.

R.p.m. regulators of the centrifugal governor type which utilize the centrifugal force of rotary weights, include a plurality of rotating and relatively sliding parts and thus may be the source of disturbances. Further, in the low r.p.m.-range the regulating force of these centrifugal governors is often unsatisfactory which may result in an uneven, seesawing" operation of the engine.

OBJECT AND SUMMARY OF THE INVENTION It is an object of the invention to eliminate the aforenoted disadvantages of the r.p.m. regulators known heretofore by providing an improved r.p.m. regulator using a fluid logic circuit.

Briefly stated, according to the invention, the r.p.m.-proportionate pressure pulses of a fluid medium are carried by conduits of different lengths to the individual control channels of a fluid logic element and the setting of the fuel control rod is varied in response to the pressure difference between the individual output flows emanating from a fluid amplifier element, the control flows of which are formed, on the one hand, of the output flow of the aforenoted fluid logic element, and, on the other hand, of a flow of constant pressure modulated by the open passage section of an arbitrarily variable throttle in the suction pipe of the internal combustion engine.

The invention will be better understood and further objects as well as advantages will become more apparent from the ensuing detailed specification of a preferred, although exemplary embodiment taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a diagrammatic illustration of the fluid r.p.m. regulator according to the invention;

FIG. 2 is a view of an element taken along arrow A of FIG.

FIG. 3 is a perspective view of the flow channels of a fluid logic element;

FIG. 4 is a perspective view of the flow channels'of a fluid amplifier element;

FIG. 5 is a diagram illustrating the alternating function between pressure and time in the individual channels of the fluid logic element shown in FIG. 3 and FIG. 6 is a diagram of a characteristic curve of an r.p.m. sensor used according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning now to FIG. 1, there is shown in broken lines a known pneumatic r.p.m. regulator mounted on a fuel injection pump 1, also shown in broken lines. With the fuel injection pump 1 there is associated a fuel control rod 3 which regulates the injected fuel quantities and which is connected at one end with a membrane 4 dividing a chamber 6 from a chamber 7. In chamber 7 there is disposed a spring 8 which opposes the pressure difference between the pressures prevailing in chambers 6 and 7 and which holds the fuel control rod 3 in its required position. The invention provides an arrangement in which the aforedescribed known structure is combined with a fluid logic circuit, now to be described, to effect control of the enginer.p.m. by causing displacement ofthe fuel control rod 3.

At one end of the cam shaft 2 of the fuel injection pump I there is fixedly secured a circular disc 9 of a pneumatic r.p.m. sensor which, as best shown in FIG. 2, is provided with a plurality ofsmall openings 10 arranged along a common circle.

Adjacent one side of the disc 9 there is disposed an ejector or blower nozzle 11 which is connected by means ofa conduit 12 to a source of pressurized fluid, not shown. At the opposite side of the disc 9, in alignment with the nozzle 11, there is disposed a pickup nozzle 13 adapted to receive the fluid emanating from the nozzle 11.

From pickup nozzle 13 there extend two conduits: a conduit 14 and a relatively longer conduit 15. Conduit 14 is attached to the right control channel 17 of a fluid logic element 16, while the conduit 15 is attached to the left control channel 18 thereof. The main flow channel 22 of the fluid logic element 16 communicates with a conduit 21 through which fluid under pressure is introduced from a fluid source (not shown) across the main channel 22 into the control chamber 23 of the fluid logic element 16 (FIG. 3). The control channels 17 and 18 merge into the control chamber 23 from the right and from the left, respectively. In order to generate the known Coandaeffect, in the lower section of control channels 17 and 18, to the right and to the left of main flow channel 22 and symmetrically to the central axis thereof, there are provided sidewalls 24 and 25 as well as a portion 26 which together define the right output channel 27 and the left output channel 28.

In a fluid logic element of the type described hereinabove, the fluid medium arriving from the main channel 22 into the control chamber 23 proceeds, due to the control flow pulses injected into chamber 23 from the control channel 17 or control channel 18, along one of the sidewalls 24 or 25 due to the Coanda-effect. This deflected condition is maintained even after the control signal ceases. As a result, the fluid medium either flows in one of the output channels 27, 28 (on-condition) or does not flow (off-condition).

The output channel 28 of the fluid logic element 16 is connected through conduit 29 with the control channel 31 of a fluid amplifier element 30, shown in FIG. 4. Fluid medium under pressure is introduced from a fluid source (not shown) through a conduit 34 and through the main flow channel 35 of the amplifier 30 into the control chamber 36 thereof. In the control chamber 36, the main stream arriving from main chan nel 35 is deflected from its course depending on the difference between the fluid quantity arriving from the control channel 31 and that arriving from the control channel 32. The percentual component of these fluid quantities determines the course of flow in such a manner that the main stream enters either the right output channel 38 or the left output channel 39 provided in the lower section of the control channels 31 and 32. Thus, in proportion with the difference between the fluid quantities arriving from control channels 31 and 32, there is generated, between the output channels 38 and 39, a multiple of the quantity difference and, as a result, a pressure difference between the two output channels is obtained.

Discharge channels 40 and 41 connected with the control chamber 36, carry away the excess fluid medium. The output channels 38 and 39 are, by means of respective conduits 42 and 43, connected with chambers 7 and 6, respectively, which serve to displace the fuel control rod 3.

With the control channel 32 of fluid amplifier element 30 there communicates a conduit 44 in which there is disposed an arbitrarily adjustable throttle 46 for a control flow to set the engine r.p.m., and which is connected with a fluid source of constant pressure, not shown. The control channel 47, disposed parallel with the control channel 31 is, through a conduit 48, also connected with a fluid source of constant pressure (not shown) and constitutes an auxiliary (bias) stream which produces a constant pressure. Thereby it is achieved that the range of r.p.m.-control which is dependent on the variable throttle valve 46 is no longer limited by the initial load exerted by spring 8. This auxiliary stream may be replaced by arranging the output channels 38 and 39 unsymmetrically with respect to the axis of the main channel 35.

OPERATION OF THE EMBODIMENT The pump cam shaft 2, together with circular disc 9, rotates at r.p.m.-responsive speeds, while blower nozzle lll emits a continuous stream of fluid directed against disc 9. Each time an opening of disc 9 is in a momentary alignment with blower nozzle 11, a fluid pulse is received by pickup nozzle 13. One part of the fluid forming a pulse enters through conduit 14 into the right control channel 17 of the fluid logic element 16 and causes the main stream arriving from the main flow channel 22 to be deflected into the output channel 28. The other part of the fluid forming the same pressure pulse enters through the longer conduit into the left control channel 18 of the fluid logic element 16 with a time lag of T see. and switches the main stream from the output channel 28 to the output channel 27.

As the disc 9 continues to rotate, 60/nN seconds later the next pulse is generated in the pickup nozzle 13. in the same manner as set forth hereinbefore, first, by virtue of the signal arriving from the conduit 14, the main stream is switched from the output channel 27 to the output channel 23 and then, by virtue of the delayed arrival of the signal from the conduit 15, the stream is switched from the output channel 28 to the output channel 27. This switching process is illustrated in FlG. 5. it is noted that n is the number of openings 10 in the circular disc 9 while N is its r.p.m. lf now the time is measured along the abscissa and the pressure along the ordinate, then curve (a) represents the pressure pulses in the control channel 17 as a function of time, curve (b) represents the pressure pulses in the control channel m as a function of time and shifted with respect to (a) by T sec., and curve (c) represents the pressure pulses in the output channel 28 as related to (a) and (b). In this case, the period (on-condition) during which the main stream flows in the output channel 28, is determined by the delay of T sec. of the impulse transmission. This delay, in turn, is a function of the difference in the length of conduits 14, 15 and is independent of the rpm. of disc 9. Since the pulse interval is determined by the r.p.m. N of the disc 9, and by the number n of openings 10, then, if n isconstant, the pulse interval is inversely proportionate to the r.p.m. N. lt follows that the average pressure P generated in the output channel 28 of the fluid logic element 16 is, as seen in FIG. 6, proportionate to the r.p.m. N and consequently, the r.p.m. may be determined by the value of P.

The pulse signals generated in the output channel 28 of the fluid logic element 16 enter through the conduit 29 into the control channel 311 ofthe fluid amplifier element 30. The pressure signal regulated by throttle 46 and carried by conduit 44 to the control channel 32 of the amplifier 30 and the aforedescribed r.p.m.-responsive pressure signals in control channel 31 are compared with one another. As a result of this comparison, there is generated in the output channels 38 and 39 of the fluid amplifier element 30--and thus also in the chambers 7 and 6, respectively,-a pressure difference which corresponds to the aforenoted differential pressure. As a result, the fuel control rod 3 is shifted into a position of equilibrium with the aid of spring 8 and thus the fuel quantities to be injected are determined.

If, for example, the load on the internal combustion engine decreases so that the torque produced by the engine exceeds the load torque, the r.p.m. increases, which results in an increase of the average pressure in the control channel 31 of the fluid amplifier element 30. Consequently, the pressure in the left output channel 39 will be higher than in the right output channel 38. As a result, the pressure in the chamber 6 will increase so that the fuel control rod 3 is displaced towards the left and, consequently, the fuel quantity to be injected is decreased. This, in turn, causes the engine r.p.m. to drop, so that the output and load torques will be equalized and the r.p.m. stabilized anew. If, conversely, the load torque of the engine increases and the r.p.m., as a result, decreases, it is the chamber 7 in which the pressure will increase and thus the fuel control rod 3 will shift towards the right, increasing thereby the fuel quantities to be injected.

The r.p.m. of the engine may be arbitrarily set by changing the flow passage section of the throttle 46, varying thereby the pressure of the fluid medium flowing in control channel 32 of the fluid amplifier element 30.

Because of the initial load exerted by the spring 8, it is not possible even if the throttle 46 is restricted beyond a certain extent to set the r.p.m. under a certain value. In order to remedy this inconvenience, the pressure in the output channel 39 is increased by the pressure of an auxiliary stream (bias) in control channel 47. Since this pressure opposes the force of spring 8, the range of displacement of the fuel control rod 3 is extended towards the left and, consequently, the r.p.m. may be set to the aforenoted certain value or thereunder.

What I claim is:

1. An r.p.m. regulator for shifting a fuel quantity control member associated with an internal combustion engine, comprising,

A means for generating a fluid pulse signal of a frequency dependent on the engine r.p.m.,

B a fluid logic element having at least two control channels and an output channel,

C conduit means for dividing said pulse signal and applying it to said control channels with a time lag with respect to one another for producing an output fluid flow of engine r.p.m.-dependent pressure in said output channel,

D means for arbitrarily varying the pressure of a control fluid flow,

E a fluid amplifier element having at least two control channels and two output channels, said output fluid flow from said fluid logic element being applied to one of said control channels of said fluid amplifier element and said control fluid flow of arbitrarily variable pressure being applied to the other of said control channels of said fluid amplifier element to produce in said output channels of said fluid amplifier element output flows having a pressure difference depending upon the fluid flows in the last named two control channels and F pressure-responsive means receiving said output flows from said fluid amplifier element and being connected to said fuel quantity control member to displace the latter to an extent dependent upon said pressure difference.

2. An r.p.m. regulator as defined in claim 1, wherein said means for generating said fluid pulse signal includes A a disc having at least one opening in its face,

B means for rotating said disc at an r.p.m. proportionate to said engine r.p.m.,

C a nozzle disposed adjacent one face of said disc and ejecting fluid theretoward,

D a pickup nozzle connected to said conduit means and disposed adjacent the other face of said disc to receive a fluid pulse when said opening in said disc is in momentary alignment with said nozzles; consecutive pulses generated during the rotation of said disc constitute said pulse signal.

3. An r.p.m. regulator as defined in claim 1, wherein said conduit means is formed of two conduits of different lengths leading from said pickup nozzle to said two control channels of said fluid logic element.

4. An r.p.m. regulator as defined in claim 1, wherein said means for arbitrarily varying the pressure of a control fluid flow includes a throttle valve disposed in a conduit connected to one of the control channels of said fluid amplifier element.

5. An r.p.m. regulator as defined in claim 1, wherein said pressure-responsive means includes A a membrane secured to said fuel quantity control member and having 1 a first face exposed to the pressure of fluid in one of the output channels of said fluid amplifier element,

2 a second, opposed face exposed to the pressure of fluid in another one of the output channels of said fluid amplifier element, and

7. An r.p.m. regulator as defined in claim 1, wherein said fluid amplifier element is provided with discharge channel means to carry away excess fluid from said fluid amplifier element. 

1. An r.p.m. regulator for shifting a fuel quantity control member associated with an internal combustion engine, comprising, A means for generating a fluid pulse signal of a frequency dependent on the engine r.p.m., B a fluid logic element having at least two control channels and an output channel, C conduit means for dividing said pulse signal and applying it to said control channels with a time lag with respect to one another for producing an output fluid flow of engine r.p.m.dependent pressure in said output channel, D means for arbitrarily varying the pressure of a control fluid flow, E a fluid amplifier element having at least two control channels and two output channels, said output fluid flow from said fluid logic element being applied to one of said control channels of said fluid amplifier element and said control fluid flow of arbitrarily variable pressure being applied to the other of said control channels of said fluid amplifier element to produce in said output channels of said fluid amplifier element output flows having a pressure difference depending upon the fluid flows in the last named two control channels and F pressure-responsive means receiving said output flows from said fluid amplifier element and being connected to said fuel quantity control member to displace the latter to an extent dependent upon said pressure difference.
 2. An r.p.m. regulatOr as defined in claim 1, wherein said means for generating said fluid pulse signal includes A a disc having at least one opening in its face, B means for rotating said disc at an r.p.m. proportionate to said engine r.p.m., C a nozzle disposed adjacent one face of said disc and ejecting fluid theretoward, D a pickup nozzle connected to said conduit means and disposed adjacent the other face of said disc to receive a fluid pulse when said opening in said disc is in momentary alignment with said nozzles; consecutive pulses generated during the rotation of said disc constitute said pulse signal.
 3. An r.p.m. regulator as defined in claim 1, wherein said conduit means is formed of two conduits of different lengths leading from said pickup nozzle to said two control channels of said fluid logic element.
 4. An r.p.m. regulator as defined in claim 1, wherein said means for arbitrarily varying the pressure of a control fluid flow includes a throttle valve disposed in a conduit connected to one of the control channels of said fluid amplifier element.
 5. An r.p.m. regulator as defined in claim 1, wherein said pressure-responsive means includes A a membrane secured to said fuel quantity control member and having 1 a first face exposed to the pressure of fluid in one of the output channels of said fluid amplifier element, 2 a second, opposed face exposed to the pressure of fluid in another one of the output channels of said fluid amplifier element, and B a spring in engagement with said membrane and counteracting said pressure difference.
 6. An r.p.m. regulator as defined in claim 5, wherein said fluid amplifier element includes and additional control channel carrying a fluid of constant pressure to equalize the force of said spring.
 7. An r.p.m. regulator as defined in claim 1, wherein said fluid amplifier element is provided with discharge channel means to carry away excess fluid from said fluid amplifier element. 